1. Field of Invention
The present invention relates to a clock control system that supplies clocks to each block in a microcomputer or the like.
2. Description of Related Art
FIG. 4 shows a related art clock frequency divider system.
Specifically, FIG. 4 shows a clock oscillator 1, a frequency divider circuit 2 and a microcomputer 3 that is equipped with blocks, such as a CPU 4, a bus 5, a peripheral circuit 6 and other circuits 7. A clock provided by the clock oscillator 1 is first divided by the frequency divider circuit 2, and the clock divided at a specified ratio is supplied to each of the blocks 4-7.
In the system described above in which a single clock from the common frequency divider circuit 2 is supplied to all of the blocks 4-7, the same clock that is supplied to a block that requires a high clock number, such as the CPU 4, is also supplied to the other blocks that may require low clock numbers, such as the bus 5, the peripheral circuit 6 and the like. Power saving is beneficial in all equipment. However, the related art system, such as the one described above, has a problem because it supplies unnecessary clock numbers, and therefore cannot reduce the power consumption through supplying a minimum clock that is required for each of the blocks.